1. Field of the Invention
This invention relates to a picture signal processing device for performing processing operations, such as synthesis, deformation or color conversion of picture signals.
2. Description of the Related Art
A picture signal processing device performs picture processing, such as synthesis or color conversion of pictures as it selects plural from plural input picture signals. For example, the picture information processing device synthesizes picture signals of two systems as it switches between the two systems using a switcher as switching means.
This picture signal processing device receives composite signals, as standard-format picture signals (shown as Composite in the drawings), Y/C signals and component signals (shown as Component in the drawings) via a switcher 141, as shown in FIG. 1. The picture signal processing device performs picture processing on the composite signals. Thus it becomes necessary to convert the Y/C signals and composite signals other than the component signals into component signals downstream of the switcher 141.
First, the composite signals are separated by a Y/C separation circuit 142 into Y and C signals so as to be then converted by a decoder 143 into Y, R-Y and B-Y signals as component signals. The Y/C signals are converted by the decoder 143 into component signals. The component signals, outputted by the decoder 143, are sent to an A/D converter 144, which then converts the component signals into digital signals based on clocks of a write clock generator 145. The digital component signals are sent to a frame synchronizer 146.
The frame synchronizer 146 writes the digital component signals in an internal frame memory based on external clock signals (shown as EXT key in the drawings) generated from the above standard format picture signals and reads out the digital component signals therefrom to adjust the frame position or color subcarrier phase in order to adjust the signals for digital multi-effect (DME) processing as later explained. The digital component signals outputted by the frame synchronizer 146 are sent to a switcher 147.
A Y/C separation circuit 148, a decoder 149, an A/D converter 150, a write clock generator 151 and a frame synchronizer 152 perform processing similar to that described above on the standard format picture signals of the other system via switcher 141. The digital component signals outputted by a frame 152 are also sent to the switcher 147. The switcher 147 is fed with Y, R-Y and B-Y digital component signals from a test pattern signal generator 153 generating test pattern signals, such as color background signals, color bar signals or grid signals.
The digital component signals via switcher 147 are sent to a two-dimensional variable low-pass filter (LPF) 154. This two-dimensional variable LPF 154 removes high-frequency components of the digital component signals for generating no aliasing in the digital component signals. The digital component signals, freed of the high-frequency components, are sent to a field memory 155, which is also fed with write and readout addresses from a system controller 157 via a DME processor 158. In keeping with instructions from the system controller 157, the DME processor 158 performs picture processing, such as picture synthesis, color conversion or geometry conversion, on the digital component signals. To this end, the system controller 157 sends data required for desired DME processing to the DME processor 158.
The DME processor 158 performs the above picture signal processing on the digital component signals from the two-dimensional LPF 154, using the field memory 155, in accordance with the addresses and data supplied from the system controller 157.
If the digital component signals are processed by deformation, pixel dropout frequently occurs in the signals read out from the field memory 155. Thus, the signals read out from the field memory 155 are sent to an interpolation circuit 156 for pre-set interpolation. The DME processed signals, outputted from the interpolation circuit 156, are sent to a data mixing circuit 156, which is also fed from the system controller 157 with the addresses same as those sent to the DME processing circuit 158, so that the addresses and data are mixed with the DME processed signals. Mixed output signals of the data mixing circuit 159 are sent to a synthesis circuit 161, which is also fed with the digital component signals delayed by a field delay circuit 160. Thus, these delayed digital component signals are mixed with the mixed output signals. A synthesized output of the synthesis circuit 161 is a signal processed by picture signal processing. The synthesized output is converted by the D/A converter 162 into analog signals which are outputted in the form of analog composite signals, Y/C signals and component signals.
Meanwhile, with the picture signal processing device shown in FIG. 1, the input/output signals are limited to the standard composite signals, Y/C signals and component signals. That is, the device cannot handle picture signals deviating from standard picture signals, such as pictures of different resolution, pictures with different transfer rates or with different picture size. Moreover, the same picture signals with different systems, such as HDTV or NTSC systems, cannot be handled in the same device. That is, the picture signal processing device cannot handle so-called free-format picture signals which are not dependent on resolution, so-called scalable-format picture signals or picture signals with different systems. As a matter of fact, the compressed pictures cannot be handled, so that switching of compressed pictures resulting from inter-frame compression cannot be switched smoothly.
It is therefore an object of the present invention to provide a picture signal processing device whereby so-called free-format picture signals which are not dependent on resolution, so-called scalable-format picture signals or picture signals with different systems can be processed with various picture processing and whereby switching of compressed pictures resulting from inter-frame compression cannot be switched smoothly.
It is another object of the present invention to provide a picture signal processing device whereby first compressed picture signals and second compressed picture signals, compressed by intra-frame compression and inter-frame compression, respectively, can be switched at desired positions and outputted.
In one aspect, the present invention provides a picture signal processing apparatus including selection means for selectively seizing a plurality of compressed pictures obtained in inter-frame compression, converting inter-frame forward predictively-coded pictures into intra-frame coded pictures, in terms of a pre-set number of frames as a unit, and modifying prediction data of bidirectional predictive-coded pictures, expansion means for expanding compressed picture signals selected by the selection means, first input/output means for inputting/outputting picture signals outputted by the expansion means, picture processing means for performing various picture processing operations on picture signals outputted by the first input/output means for outputting processed picture signals, compression means for compressing the processed picture signals outputted by the picture processing means for outputting compressed processed picture signals, second input/output means for inputting/outputting the compressed picture signals outputted by the expansion means, and control means for controlling the selecting operation by the selection means, expansion processing by the expansion means, input/output processing by the first input/output means, picture processing by the picture processing means, compression by the compression means and input/output processing by the second input/output means.
Preferably, the selection means includes means for suppressing increase in the information volume caused by changes in the prediction data of the bidirectional predictive-coded pictures.
Preferably, the expansion means reads out the attribute information including the compression/non-compression discrimination information, information on the compression system, the information on the picture size dependent on the number of pixels in the horizontal and vertical directions, the information on the size of the processing screen designating a processing area, the information on the picture system, or the input/output signal rate information, and sends the read-out attribute information to the control means.
Preferably, the first input/output means includes a system converter for converting the system of picture signals and a storage unit having a sufficient capacity irrelevant to the picture size of the picture signals.
Preferably, the second input/output means includes a storage unit having a sufficient capacity irrelevant to the picture size of the picture signals.
Preferably, the compression means has a system converter for converting the system of the picture signals.
With the picture signal processing apparatus of the present invention, since selection means selectively seizes plural inter-frame compressed pictures, converts the inter-frame forward predictively-coded pictures into intra-frame coded pictures, in terms of a pre-set number of frames as a unit, and modifies prediction data of bidirectional predictive-coded pictures, inter-frame coded compressed pictures can be switched smoothly. Moreover, since the expansion means expands the compressed input picture signals to output picture signals, and the first input/output means input/output the picture signals under control by the control means, while the first input/output means input or output the picture signals under control by the control means, the picture processing means perform various picture processing operations on the picture signals to output processed picture signals and the compression means compress the processed picture signals and the second input/output means input or output the compressed processed picture signals, various picture processing operations can be performed on so-called free-format picture signals, picture signals not dependent on the transfer rate, so-called scalable format picture signals or picture signals of different systems.
In another aspect, the present invention provides a picture signal processing apparatus including control means for generating signals indicating switching positions, processing means for performing pre-set processing on first compressed picture signals and second compressed picture signals, compressed by intra-frame compression and inter-frame compression, respectively, based on the signals specifying the switching positions supplied from the control means, and selection means. The processing means converts P-pictures of the first compressed picture signals associated with the signals specifying the switching positions into I-pictures, modify prediction data for B-pictures of the first compressed picture signals associated with the signals specifying the switching positions, convert P-pictures of the second compressed picture signals associated with the signals specifying the switching positions into I-pictures, and modify prediction data for B-pictures associated with the signals specifying the switching positions. The selection means selectively outputs the first compressed picture signals and the second compressed picture signals, converted or modified by the processing means, based on the signals specifying the switching positions.